Barosaurus was a huge, long-necked, plant-eating dinosaur that lived during the Jurassic period, about 156 to 145 million years ago. The name Barosaurus means "Heavy Lizard"; this giant was named by paleontologist Othniel C. Marsh in 1890.

Anatomy: Barosaurus was huge and slow-moving. It had a long neck, small head, long, whip-like tail, and small brain. This diplodocid sauropod was about 66 to 88 feet (20-27 m) long, weighing roughly 44 tons (40000 kg). Its femur (thigh bone) was 8.2 ft (2.5 m) long - bigger than a human being. Barosaurus' primary defense against predators was its size.

Fossils: Barosaurus fossils have been found in western North America and East Africa.